This paper has attempted to obtain better constraints on the sources of the trend and annual components of both global sea-level pressure (SLP) and variations in the Earth's rotation (RP – coordinates of the rotation pole - and lod – length of day), and to test the hypothesis that there might be a direct or indirect causal link between them. In a previous study, it had been shown, using iterative singular spectrum analysis (iSSA), that the mean sea level atmospheric pressure (SLP) contains, in addition to a weak trend, a dozen quasi-periodic or periodic components (\(\sim \) 130, 90, 50, 22, 15, 4, 1.8 yr), the annual cycle and its first three harmonics [1]}. These periods were already known to be characteristic of the space-time evolution of the Earth's rotation axis (RP) and had been identified in many characteristic features of solar and terrestrial physics. Polar drift and the free Chandler wobble having been studied in earlier papers [2]}, [1]}, [4]}, there remained a need of a similar analysis of the annual and semi-annual components of SLP, RP and lod. Most older and many recent analyses suggested more or less tentatively that the annual oscillation in the RP was due to a geographical redistribution of crustal and atmospheric masses, though it was agreed that quantitative modeling of this was unsatisfactory [5]}.
